The invention relates to record carriers. Such a record carrier has a recording layer in which information can be (a) written by changing an area of the recording layer having an amorphous structure by means of write pulses of a radiation beam into an information area having a crystalline structure and (b) erased by heating an information area above the melting point of the recording layer by means of erase pulses of a radiation beam.
A system which is capable of writing and erasing information on such a record carrier is known from an article entitled "Optical memory" by P. Chaudhari and C. B. Zarowin in the IBM Technical Disclosure Bulletin, vol. 16, no. 2, July 1973, pp. 568 and 569. In that system, a crystalline information area in an initially amorphous material is written by means of a pulsed and focused radiation beam. The information area is erased by rendering the material amorphous again by means of an erase pulse at the information area. The erase pulse has a shorter pulse duration and a larger amplitude than the write pulse. However, it has been found that upon reading information which has been written after erasure, a read signal is obtained which is not optimum and has a signal-to-noise ratio which is too low.